At the present time there is a need for a practical means of determining the cement-to-water ratio in a cement mix at the critical time just before it is poured on the job. Laboratory tests have been developed, but they take at least one-half hour to complete in a laboratory environment and are thus normally not practical for field testing of concrete mixes. As a result of the lack of on-the-job determination of the cement-to-water ratio, there is a tendency to overdesign concrete structures to give an additional safety factor to allow for variances from the cement-to-water ratio specification. This adds unnecessary expense to the concrete structure.
Furthermore, if the cement-to-water ratio in the cement mix used on a job does not meet specifications, the result may be a structure with an undetected hazardous strength deficiency or one which must be replaced or strengthened by structural addition before final inspection approval can be achieved on the job. Thus, six groups have a vital interest in having a means for accurate determination of the cement-to-water ratio in a mix before the pour: (1) the designer of the structure; (2) the structural engineers specifying the mix; (3) the supplier of the concrete mix; (4) the contractor using the mix; (5) the inspection personnel; and (6) the owner of the structure.